THE CRINOIDEA 



the axial cords (Fig. XLVIIL). The depressions between these folds 

 are often deep, and it is in them that the pores are said to lie. It 

 is supposed that such genera have no madreporite, and that the 

 pores aerated the rectum or a blind extension thereof, for the 





Ventral surface of Aiitedon lijiiln, 

 diagrammatised from various authori- 

 ties, x 4 diam. As, anus ; 0, mouth ; 

 p, pinnules; s, samili ; /'./>, \\atrr- 

 pores. 



Vertical section through tegmen and under- 

 lying structures of Antedon biftda. Shows four 

 pores, with ciliated funnels (o/), piercing the 

 integument (teg), and communicating by a 

 water-vessel (wv) with lacunar vessels (/) in the 

 connective tissue of the mesentery (?u). The 

 funnels are cut through in different directions. 

 /, fibrous layer of integument; c, coelomic 

 cavities ; n, gut-wall, showing outer fibrous 

 layer, epithelium, and inner cuticle. (After 

 Vogt & Jung, ]SS(5.) Greatly magnified. 



anus often opens low down on the anterior face of the tube. The 

 statement has been definitely disproved for many forms hitherto 

 said to have such pores. But Wachsmuth & Springer (1897, 

 pi. vii., figs. 26, 5, 6, 9) support it by figures which, if correct and 



FIG. XLVIII. 



Structure of the anal tube in an Inadunate Crinoid, Mastiyocrinus loreus. 1, plates in 

 normal position, from left edge of distal third of tube ; /, transverse folds connecting the main 

 axial ridges, r. 2, plates from the proximal third, disturbed and exposing the articular facets 

 (art) of the axial ridge. (After Bather, lS9i.) X 10 diam. 



correctly interpreted, prove it for some species up to the hilt 

 and much further. For they show pores not only on the sutures, 

 but penetrating the plates ; not only in the interaxial depressions, 

 but on the axial folds ; not only in the tube, but in the dorsal 

 cup. 



The last organ of which the modifications need be considered 



